If you want to see some fun dog training with whistles search for videos of sheep dogs or waterfowl retrievers. My cousin trained a couple of black labs to be

If you want to see some fun dog training with whistles search for videos of sheep dogs or waterfowl retrievers. My cousin trained a couple of black labs to be waterfowl retrievers. I saw him in training throw out a training "duck" and hold the labs at this side with just a look. Then he whistled and they took off. About 5 feet from the "duck" he whistled again and they stopped. The dogs wanted to get to the "duck" so bad they looked like they were vibrating. He kept them there for a good 30 seconds before whistling again to signal for them to retrieve it. It was pretty cool to watch. Not quite as cool but we have a "shock" collar on our cat to keep him off the neighbor's porch furniture. Our neighbor is very, very allergic to cats. It is activated by a 10' diameter transmitter placed under their furniture and beeps like crazy for 10 seconds before it does anything - a couple of beeps sets my cat running. For some reason (maybe after seeing my cousin do it?) I started doing a specific whistle pattern when the cat comes in the house with the collar on. That will now stop the cat dead in his tracks and he will wait for me to take it off. The reverse is true also - if he sneaks out of the house without it on I can do the same whistle and he will stop and wait for me to put it on him.